Checking isnan value by javascript is not working

Question

1.00/5 (1 vote)

See more:

I am trying to do login and logout task. If User login then alert login value else alert Empty but it is not properly set. it always return "Empty" Value even though "gg" has value.

<button id="btn" onclick="Test()" style="width:150px; height:40px;background-color:blue;color:white;">Pay Online</button>

function Test(){

            var re= parseInt(sessionStorage.getItem("myUser1"));
            document.getElementById('loveuser').value=re;
            var gg=document.getElementById('loveuser');

            if(!isNaN(gg)){
                alert(gg);
            }else{
                alert("Empty");
            }

        }

"gg" always retrun "Empty" Not "gg" value even though it has value. What's wrong?.

What I have tried:

trying from two days via online

Posted 28-Feb-23 18:38pm

MAHESH WAGHELA

Updated 28-Feb-23 22:14pm

Add a Solution

Comments

Member 15627495 1-Mar-23 1:31am

it seems "sessionStorage.getItem("myUser1")" is empty..
your isNaN works.

https://developer.mozilla.org/fr/docs/Web/JavaScript/Reference/Global_Objects/isNaN

MAHESH WAGHELA 1-Mar-23 2:46am

Thx Its Now Working

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Richard Deeming · Accepted Answer · 2023-02-28T22:14:00

Quote:

JavaScript

var gg=document.getElementById('loveuser');
if (!isNaN(gg)) {

Your gg variable contains the HTML element itself, not the value of that element.

An HTML element is not a number, so your code will always display "Empty".

Change your code to test the value of the element instead.